Could we have predicted that Sam Cassidy, the Santa Clara Valley Transportation Authority employee who killed nine of his colleagues before turning the gun on him, would have committed such a crime?

This is what VTA staff and local leaders are now trying to answer through an investigation into Cassidy’s personal history as a VTA employee following the May 26 mass shooting.

At the moment, the answer is: no.

“So far there is no indication in Cassidy’s VTA personal file of any formal discipline for threatening behavior or violence during her 20-year career with VTA,” VTA said Thursday in a statement.

Cassidy’s file may not have indicated violent behavior, but her file was not blank.

He had been sent home for insubordination because he refused to comply with company policy of disconnecting a two-way radio which was necessary to perform his job in July 2019.

He declined to sit for CPR certification in October 2020 due to concerns about COVID-19.

And most recently, in November 2020, he left work without permission due to frustration with clocking in. He also used the radio station for personal communications instead of operational matters, which is against VTA policy.

“He left work without permission instead of fixing the problem,” the VTA said.

However, there is one case that may require further investigation.

On January 29, 2020, a verbal altercation between Cassidy and another VTA employee was reported to VTA Employee Relations and VTA’s Civil Rights Office.

In an email to VTA management, an employee wrote that Cassidy had been yelling at a coworker for about two to three minutes, calling the person “the most corrupt person in VTA.”

Many representatives and colleagues from the Amalgamated Transit Union were there when the altercation erupted and an ATU representative told Cassidy that “this is neither the time nor the place.”

The altercation subsided at that point, however, when questioned by a supervisor, a colleague reported that another anonymous employee said, “He (Cassidy) scares me. If someone had to go by the post, that would be him. “

But since there were no other disciplinary incidents of concern, there was no further investigation and disciplinary action was referred to Cassidy’s management.

The VTA said it is still reviewing “thousands of pages of documents including emails, attachments and other documents” which require review and will be released “as soon as possible”, and with regard to the confidentiality of colleagues.

The VTA also said that among the thousands of documents it had at no time found information about Cassidy provided by any federal agency, including the Department of Homeland Security.

The Wall Street Journal reported that Cassidy was arrested by U.S. Customs and Border Protection after traveling to the Philippines. There, authorities found books on terrorism and a notebook containing complaints about the ATV in Cassidy’s possession.

Santa Clara County District Attorney Jeff Rosen said federal agents failed to notify local law enforcement.

At a press conference Tuesday at San Jose City Hall, Rosen said he was working with San Jose Mayor Sam Liccardo to create protocols for sharing information with different agencies responsible for l law enforcement to prevent this from happening again.

The VTA will continue to release documents regarding Cassidy if more relevant information is discovered.

Nine VTA employees were shot dead in the mass shooting, including Jose Dejesus Hernandez III, 35, of Dublin. The other victims were Adrian Balleza, 29; Taptejdeep Singh, 36; Michel Joseph Rudometkin, 40 years old; Paul Delacruz Megia, 42 years old; Alex Ward Fritch, 49; Timothée Michael Romo, 49 years old; Abdolvahab Alaghmandan, 63 years old; and Lars Kepler Lane, 63.